The invention in this application is at times described in relative terms, such as “up” and “down,” for ease of explanation. These terms generally are to be understood in relation to the orientation of the wear assembly as illustrated in FIG. 1. However, the wear assembly can be placed in all kinds of orientations, and the relative terms used to describe the invention are not intended to be a limitation of the invention.
Wear parts, such as teeth and shrouds, have long been secured along the digging edges of various excavators (e.g., the front lip of a bucket for a front end loader) to break up the earthen material to be collected and to protect the digging edge from premature wear. To facilitate replacement of the wear parts and reduce the amount of material needing frequent replacement, the wear parts are typically composed of multiple parts. As an example, the wear parts may include an adapter, a wear point or tip, and a lock to removably secure the wear member to the adapter.
An adapter is a base that is fixed to the digging edge of an excavator by welding, mechanical attachment or being cast as an integral portion of the bucket lip. The adapter itself may have multiple parts, particularly in larger sized teeth, but is commonly a single component. In any event, the adapter includes a forwardly projecting nose shaped to securely hold the wear member in place. In an excavating tooth, the wear member is a point or tip that has a generally wedge-shaped configuration with top and bottom walls that converge to a digging edge. The base end of the point includes a rearwardly opening socket to receive the adapter nose. The lock, typically in the form of a pin, is inserted into a passage formed by an opening in the adapter nose that aligns with openings in opposite walls of the point. The passage may extend through a central portion of the nose either vertically or horizontally, or be defined externally of the nose to receive an external lock, for example, as disclosed in U.S. Pat. No. 4,965,945, which is hereby incorporated by reference.
Although the passage receiving the lock may be linear or curved, the sides of the lock and the walls of the passage receiving the lock have in the past been defined by generally parallel surfaces. As a result, the sides of the lock slide against the walls of the passage in face-to-face contact as the lock is being inserted into or removed from the tooth. Moreover, it is important to maintain the lock in the defined passage so that the point is not lost. Loss of the point not only leads to premature wearing of the adapter, but may also damage downstream machinery intended to process the excavated material. Accordingly, the lock is fit tightly within the defined passage to inhibit its ejection or loss. As can be appreciated, this sliding action of the lock generates significant frictional resistance. In the past, a large hammer has been needed to force the lock into and out of the passage. This tends to be an onerous and time-consuming task for the operator in the field.
The present invention solves the difficulties of inserting and removing the lock via a novel construction that enables the lock to be inserted into and removed out of the wear assembly (e.g., a tooth) without the need for repeated hammer blows. More specifically, a tapered lock is received within a complementary opening whereby the lock can be inserted and removed by a prying tool. The use of such a cooperative lock and opening can be used to secure different types of wear members (e.g., points and shrouds) usable in excavating operations.
In one aspect of the invention, the wear assembly has a tapered opening that is adapted to receive a complementary shaped lock. In one construction, the opening is tapered such that the front and rear walls converge as they extend away from the opening's inlet end. In a preferred embodiment, the opening narrows in generally three perpendicular directions. The opening also preferably includes a stop to releaseably retain the lock in the opening and a notch to better help prevent twisting of the lock under load.
In another aspect of the invention, the lock includes a body that generally converges toward one end to define a tapered configuration. Due to the tapered shape of the lock, as opposed to a lock with generally parallel sidewalls, the lock does not slide in face-to-face contact with the sidewalls of the passage and generate high frictional resistance as it is being placed into and out of the passage. Accordingly, the lock can be pried into and out of the passage without the use of a hammer. In a preferred aspect of the invention, the prying tool is a member that rotates to release the latch of the lock and to pull the lock from the opening.
In one preferred embodiment of the invention, the wear member (e.g., a point) has an ear that projects rearwardly from the socket defined to receive the adapter nose. The ear includes a tapered slot or opening to receive and support the tapered lock when fully inserted, but without the frictional sliding against the sides of the slot when only partially fit into the slot. The full face-to-face engagement between the lock and the slot only occurs when the lock has been fully inserted. The lock has a latch that cooperates with a formation in the tooth to hold the lock in place during use of the tooth.